This application claims priority to Taiwan Patent Application No. 091110478 entitled xe2x80x9cScissors-like Linkage Structure, Key Switch Including the Structure and Method of Assembling the Samexe2x80x9d, filed May 20, 2002.
The present invention generally relates to a scissors-like linkage structure for use with a key switch and a method of manufacturing the same and, more particularly, to a scissors-like linkage structure with a slot having portions of different diameters to accommodate a pivot in different configurations, a key switch including the structure, and a method of assembling the same.
Keyboards are widely used with various devices, such as computers, to input characters and numerals. To make a key on the keyboard easy to depress, the key is usually designed to function no matter where a force is exerted on the key cap. In other words, even though the force is exerted on the edge of the cap, the force is generally equally distributed over the entire surface of the cap using a scissors-like linkage structure for each key. Furthermore, while space is especially an important consideration in designing for keyboards of portable computing devices, key switches with scissors-like linkage structure are often the solution.
Typically, a scissors-like linkage structure includes an inner arm and an outer arm, which are formed by the injection mold technique. Connection mechanisms are provided about on the middle portion of the inner and outer arms, so that the inner and outer arms are rotatably connected with each other to form the scissors-like linkage structure. However, in the conventional connection mechanism, the inner arm and the outer arm must be respectively formed on two independent areas by the injection mold process. Therefore, the necessary area for forming the scissors-like linkage structure is relatively large, resulting in the increase of the manufacture cost and the complication of assembling the inner and outer arms.
During the assembly of the scissors-like linkage structure, a step of separating the inner arm and the outer arm is firstly performed. Then, the two independent arms are sophisticatedly connected through the connection mechanism to form the scissors-like linkage structure. Therefore, the assembly process is relatively complicated and time-consuming, which induces the high assembly cost.
Therefore, there is a need to provide a scissors-like linkage structure to reduce the production cost and simplify the assembly process.
It is an aspect of the present invention to provide a scissors-like linkage structure for use with a key switch. The scissors-like structure has a slot including portions of different diameters, which are configured to selectively accommodate a pivot in different configurations. When the structure is formed, the pivot is located in the slot portion of larger diameter, which reduces the necessary area of producing the structure and increases the production yield by one injection mode process, and therefore the production cost per each injection mode process is reduced. By moving the pivot to the portion of smaller diameter to engage with a wall of the smaller portion, the assembly of the structure is completed at a lower assembly cost due to the simplification of the assembly process.
It is another aspect of the present invention to provide a scissors-like linkage structure and a key switch having the structure. The scissors-like linkage structure includes a first arm and a second arm. The first arm has a pivot. The second arm has a slot, which has a first portion and a second portion. The first portion is larger than the second portion in diameter. The second portion defines a wall. The pivot of the first arm selectively moves to the first portion and the second portion of the slot of the second arm. When the pivot moves to the second portion to engage with the wall of the second portion, the first arm is rotatably connected with the second arm in a first configuration. When the pivot of the first arm moves to the first portion of the second arm, the first arm and said second arm are in a second configuration.
The scissors-like linkage structure further includes a mechanism to enhance the connection when the first and second arms are in the first configuration. In a first embodiment, a protrusion is optionally provided on a sidewall of the first arm or the second arm facing the other. When the first arm and the second arm are in the first configuration, the protrusion exemplarily provided on the sidewall of the first arm contacts the second arm so that the first and second arms are closely connected. In a second embodiment, the first arm and the second arm respectively have corresponding side-edges in a complementary shape. When the first arm and the second arm are in the first configuration, the first arm movably touches the second arm through the side-edges. In a third embodiment, the second arm further includes a seal part provided on a side of the second portion. When the first arm and the second arm are in the first configuration, the seal part is configured to contact an end portion of the pivot.
It is a further aspect of the present invention to provide a method for assembling the scissors-like linkage structure. The method includes a step of forming the scissors-like linkage structure by one injection mold process. The pivot is located in the first portion of the slot after the process is completed. Then, the pivot is moved in the slot to engage with the second portion.